Stop Apple Watch 4 Charging Beeps

When first placed on its charging cable, my Apple Watch Series 4 beeps even though it is in Do Not Disturb mode. It also beeps throughout the night, waking my wife and I up. My theory is that it beeps when it becomes fully charged and then, slowly discharges and recharges, beeping once more when it becomes fully charged in the next cycle. The only way to prevent the beeps is by not charging it during the night. All of the plastic has been removed from Apple’s charging unit and cord and everything is plugged in properly. Any ideas how to charge the Apple Watch Series 4 properly at night?